Boris Johnson has apologised for suggesting that a British woman jailed in Iran was teaching journalism when she was arrested during a visit to her Iranian relatives.
"I do apologise, and of course I retract any suggestion that she was there in a professional capacity".
The Iranian authorities seized on Mr Johnson's remarks and are considering charging Ms Zaghari-Ratcliffe with further offences which could keep her imprisoned in Tehran for a number of years.
The judiciary have threatened to extend her sentence as a result of the Foreign Secretary's comments.
According to her husband, Richard Ratcliffe, the British mother-of-one now has serious concerns she may have developed breast cancer since she was wrongfully interned by the Iranian regime.
"New lumps had been identified in each of her breasts", he said.
Environment Secretary Michael Gove came under fire after appearing to cast doubt over her actions in the run up to her arrest. He was very clear in what he said, and he was wrong. Her family insist she was in the country on holiday. It wasn't for any other goal.
Taking such a measure would effectively escalate the case from an individual consular matter to a formal legal dispute between Britain and Iran, BBC diplomatic correspondent James Landale said.
Describing a phone call with his wife, Richard Ratcliffe said that lumps had been found in her breasts that required an ultrasound scan, that her state of mind had deteriorated, and that she was now "on the verge of a nervous breakdown". He told BBC Radio 4's Today programme: "I don't think it's helpful for Nazanin at this point". He has urged Johnson to take him on his forthcoming diplomatic mission to Tehran amid growing fears over her health.
Labour MP Yvette Cooper told Mr Johnson that "words matter", saying Mr Johnson can not keep "shrugging off" comments that are "inaccurate" or "damaging".
Ratcliffe reiterated his view that Johnson's resignation would not help his wife's case.
Richard Ratcliffe said his wife Nazanin had "expressed anger" at the Foreign Secretary over the "shambles" her case has become, but he did not believe Mr Johnson should be forced to quit.
After both Ratcliffe and the United Kingdom government maintained she was there for a holiday, Gove added: "I take exactly her husband's assurances in that regard".
In a statement last night he said: "The report on Saturday repeated the argument that the Foreign Secretary had revealed Nazanin's crimes, which he had been reluctant to comment on".
He added that the Foreign Secretary "undertook to look seriously at the prospect" of allowing him to join his planned visit to Iran in the coming weeks.
"The honourable members opposite must have heard that from me about a dozen times".
Zaghari-Ratcliffe's fate become a major political issue in Britain after Johnson made remarks on November 1 that appeared to cast doubt on statements from her employer. "They've kissed and made up", the Tory MP said. But her husband has been fighting for this to be elevated to diplomatic protection.
Mr Ratcliffe said he spoke to Mr Johnson for about 20 minutes, during which the Cabinet minister said he was "deeply sorry for Nazanin's suffering".
Things didn't get much better after that. I should have been clearer. "I don't know whether that will be possible but we will see what we can do". I don't think it's helpful also in terms of how that looks in Iran, for me to be looking like I'm playing politics.
Ms Zaghari-Ratcliffe was jailed for five years in September on allegations of spying and attempting to topple the Iranian government.